Prevalence of the CCR5-∆32 Allelic Frequencies in 43 Populations of India. Our data for the distribution of CCR5-∆32 suggests that it is either absent or present at low frequencies (0.62-5%) in most of the studied ethnic Indian populations, and the overall presence of CCR5-∆32 in India is only 1.1% (Table 1). It was also observed that the homozygous mutation is absent in all the studied populations. The heterozygous mutation was present in 13 of the 43 studied ethnic populations of India. It was present in nine of the 17 populations of North India analyzed for CCR5-∆32 mutations, with a frequency varying from 0.79 to 5.0%. Seven populations of the Eastern and Western Indian states do not have any such mutation. However, the mutation was found to be present in four of the 19 analyzed populations of South India with frequencies varying from 0.62 to 1.4%.

Latitude-Wise North-South Decreasing Cline For CCR5-∆32 Frequencies in India. The allelic distribution data presented in Table 1 exhibits a low allelic frequency for CCR5-Δ32 as we move toward the lower latitude, which implies that North Indians have the highest frequency distribution (0.79-5.0%) decreasing to 0.62-1.4% in South Indians. Amid all the latitudinal values, the highest allelic frequency of CCR5-Δ32 was observed at latitude 25.10 N (5.0%, χ2 value 0.1385), which corresponds to the Northern region of India (Uttar Pradesh) as compared to the smallest at latitude 18.31 N (0.62% χ2 value 0.0031) corresponding to the Southern region of India (Maharashtra). The Δ32 allele frequencies vs. latitude plots (Figure 3) present a clearer picture of the southward decline of CCR5-∆32. Thus, it is clear that there is a southward decline in the CCR5-Δ32 allelic frequency in India.

Enfeebled Δ32 Values in South Indian Populations. Our results, presented in Figure 3, suggest that the mean allelic frequency of CCR5-Δ32 was three-fold higher in North India in comparison to South India. The χ2 analyses further suggest that the prevalence of CCR5-Δ32 is significantly low (χ2= 4.032, p <0.05) in South India than North India.